#include <stdio.h>
#include <stdlib.h>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[]) {
	int cm = 0;
	scanf("%d",&cm);
	int a = 0;
	a = cm/30.48;
	printf("%d",a);
	return 0;
}
